Build it.

src/modules/partition/CMakeLists.txt

@@ -25,6 +25,7 @@ calamares_add_plugin( partition
         core/ColorUtils.cpp
         core/DeviceModel.cpp
         core/KPMHelpers.cpp
+        core/OsproberEntry.cpp
         core/PartitionActions.cpp
         core/PartitionCoreModule.cpp
         core/PartitionInfo.cpp